Thread tensioning apparatus



Aug. 19, 1-969 I v, HARVEY ET AL 3,461,718

THREAD TENSIONING APPARATUS Filed Jan. 5. 1967 5 Sheets-Sheet 1 J. v.HA'fRVEY ET AL THREAD TENSIONING APPARATUS Aug. 19, 1969 3 Sheets-Sheet2 Filed Jan. 5. 1967 Filed Jan. 5. 1967 THREAD TENSIONING APPARATUS 3Shee ts-Sheet S V-SP x5:

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50 .50 o 1 i I 1 50 50 f ce 44646 United States Patent 3,461,718 THREADTENSIONING APPARATUS John Vipond Harvey and John Rowson Thompson,Kingston, Ontario, Canada, assignors, by mesne assignments,

to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporationof Delaware Filed Jan. 5, 1967, Ser. No. 607,419 Int. Cl. G011: 3/28;G011 /04 US. Cl. 73-955 6 Claims ABSTRACT OF THE DISCLOSURE Theyarn-handling apparatus has clamps and a tensioning device which areactivated in sequence to stop, clamp and tension a length of threadadvancing to an aspirator. At the conclusion of a timed period forphysical testing, the various elements are deactivated in reversesequence. After another timed period, there is an automatic repetitionof the same sequences.

. a tensioning device adapted to tension the clamped length of threadand a means for activating and deactivating the clamps and tensioningdevice in timed sequence.

Various details of the apparatus and its operation Will be apparent fromthe following specification wherein reference is made to theaccompanying drawings in which:

FIGURE 1 is a front elevation showing one form of the apparatus;

FIG. 2 is a perspective View from the rear of the apparatus showing adrive roll mechanism for metering thread back from the aspirator;

FIG. 3 is a sectional view taken on line III-III of FIG. 1, showing thetensioning mechanism; and

FIG. 4 is a schematic diagram of pneumatic controls for various partswhich engage the thread.

Referring to FIG. 1, the thread-engaging parts are shown mounted on afront panel 1. Thread comes from a package or other source (not shown),passes through a pigtail guide 2 and is withdrawn under low tension byan aspirator 3. A first clamp has a movable top piece 4 with three pins5, a stationary bottom piece 6 with four pins 5, three neoprene pads 7between the four pins of the bottom piece 6 and a single-actingpiston-cylinder assembly 8. A second clamp has a stainless steel roll 9supported on a bracket 10, a neoprene faced roll 11 reciprocably mountedby a yoke 12 and a single-acting piston-cylinder assembly 13.Intermediate the clamps,

there is a tensioning device which includes two pulleys.

14, 15 and between them is located another pulley 16 which movesdownwardly in a slot 17 in front panel 1 to tension the thread. Thetesting equipment includes noncontacting thread vibrator 18 and avibration detector 19. The thread line is drawn past two positioningguides 20, 21. In a use embodiment, vibrator 18 is a two-inch transistorradio speaker positioned closely adjacent the thread line and detector19 includes both an ultra miniature lamp (Chicago CMB-666) and a phototransistor (Phillips OCP71). As explained more fully in connection withFIG. 4, the overall apparatus is controlled from a push-button 22 and atoggle switch 23.

A roll clamp drive mechanism for metering thread back from aspirator 3is shown in FIG. 2. The steel roll 9 is keyed to a shaft 25 which isconnected to a pinion 24. The pinion 24 is driven by a rack 26 and therack is moved by a single-acting piston-cylinder assembly 27.

As shown in FIG. 3, the tensioning device has movable pulley 16rotatably mounted on a shaft 28 which, in turn, is pivotally mounted ona hanger 29. Adjacent pulley 16, there is a tensioning weight 30 whichcan be varied for dilferent thread deniers. A counterweight 31comprising two round knurled nuts serves to balance the tensioning armwith the tensioning weight 30 removed. The spring in a single-actingpiston-cylinder assembly 32 normally holds a plate 33 and a liftingcollar 34 in the raised position. Lifting collar 34 is attached to shaft28. When in the raised position, pulley 16 is clear of the thread line.When plate 33 is lowered, pulley 1'6 rests on and tensions the thread.

With reference to FIG. 4, compressed air from a supply source 35 flowsthrough valve 22 (or 23) and a double check valve 39 to one of the pilotactuators of a fourway double acting spool valve 42. This opens thevalve and allows air to flow through a flow control-and-check valve 50(e.g., a Clippard MFC-2) into the double acting piston-cylinder assembly38 of a sequence control timer. Assembly 38 has a plunger 51 which movesout and trips five poppet valves 43-47 in sequence. As these valves aretripped, they allow air to flow through two-way flow control valves 52to the decelerator clamp cylinder 8, the roll clamp cylinder 13, thetensioning arm cylinder 32 and the metering back cylinder 27. The fifthpoppet valve 47 allows air to flow to the pilot actuator on a spoolvalve 41 which opens and passes air from source 35 through a flowcontrol-and-check valve 50 to the double-acting piston-cylinder assembly37 of a measurement timer. In its retraction, plunger 53 of assembly 37opens a poppet valve 48 which in turn activates the other pilot actuatorof spool valve 42. This causes plunger 51 to retract into assembly 38,sequentially releasing the air from cylinders 27, 32, 13, 8 and allowingtheir plungers to retract by spring action, under the control of valves52. The pilot actuator on a spool valve 40 is also activated, allowingair to flow into the double-acting piston-cylinder assembly 36 of astripping timer. The cycle is completed when plunger 54 of assembly 36completes its stroke and opens the poppet valve 49.

To operate the apparatus of the present invention, thread is taken froma package, fed into the aspirator 3 and then drawn from left to rightacross the face of the apparatus and through the pigtail 2. The threadis stripped ofi the package and runs along the thread line A shown inFIG. 1. Automatic testing commences when the cycling Valve 23 is placedon the on position, permitting air to flow from source 35 through poppetvalve 49 and check valve 39. The plunger 51 of assembly 38 moves out ata controlled rate and opens the first poppet valve 43. This activatesthe decelerator clamp pneumatic cylinder 8 which moves the top clamp 4downwards at a controlled rate. Speed decreases as the thread passes ina zigzag line between the pins 5 and the thread is finally brought torest and gripped between the pins of the top clamp 4 and the neoprenepads 7. The opening of the first poppet valve 43 also activates thespool valve 40 for stripping timer assembly 36 and the plunger 54 isextended in preparation for the next cycle. Plunger 51 opens the secondpoppet valve 44 which activates the roll clamp pneumatic cylinder 13.This brings the neoprene faced roll 11 down to grip the thread againststeel roll 9. The tensioning arm cylinder 32 is activated whenthe thirdpoppet valve 45 is opened, and the plate 33 is moved downwards. Thetensioning arm mechanism moves down with plate 33 until pulley 16engages with and rests on the thread between pulleys 14 and 15. At theinstant pulley 16 contacts the thread, plunger 51 of the sequence timerassembly 38 opens the fourth poppet valve 46 and the metering backcylinder 27 is activated. The rack 26 then moves downwards, rotatingpinion 24 and steel roll 9. A short length of thread is metered backbetween the steel roll 9 and the neoprene faced roll 11. This meteredlength allows pulley 16 to drop below and between pulleys 14, to aposition of rest where the thread is tensioned by weight 30. Thisconfiguration of the thread line has been designated B in FIG. 1. Sincethe lengths of thread line B between pulleys 14, 15 are nearly vertical,any small change that takes place in the length between the two clampswill have little effect on thread tension. Thus, for practical purposes,a known length of thread is tensioned by a known amount. The threadtension can be varied for different deniers and types of thread byvarying the magnitude of the tensioning weight 30.

The fifth poppet valve 47 is opened by plunger 51 and activates thespool valve 41 for measurement timer assembly 37. This determines thetime interval during which a physical test is carried out on the thread.In the illustrated apparatus, the physical test is facilitated bystopping a known length of tensioned thread in close proximity tovibrator 18 and detector 19. Thread vibrations cause the incident lightto fluctuate and induce a fluctuating voltage in the cell circuit.Usable outputs are obtained by coupling detector 19 to an electroniccounter 55 (e.g., a Hewlett-Packard 5223L digital counter) and anautomatic recorder 56 (e.g., a Hewlett-Packard 562A digital recorder).

After the period of time for the physical test has elapsed, retractingplunger 53 opens the poppet valve 48. This reverses the spool valve 42for sequence timer assembly 38 and plunger 51 commences its return ordeactivation stroke. The compressed air is first cut off at poppet valve47. The return spring actuates spool valve 41 and plunger 53 moves outof measurement timer cylinder 37. Next, the metering back cylinder 27 isdeactivated, and the return spring moves rack 26 upwards. Pinion 24 andthe steel roll 11 rotate and the short length of thread metered back inthe previous operation is withdrawn by aspirator 3. As plunger 51retracts, poppet valve 45 closes and a return spring in the tensioningarm cylinder 32 raises the plate 33 which raises the tensioning armmechanism. Shaft 28 pivots about its mount on hanger 29 and raises thepulley 16 clear of the thread line. Air is then released from the rollclamp cylinder 13 and the return spring raises neoprene roll 11 fromsteel roll 9, releasing the thread. Plunger 51 then closes poppet valve43 which releases the air and allows the return spring in deceleratorclamp cylinder 8 to raise top clamp 4 and release the thread. As thethread is no longer gripped by either clamp, aspirator 3 startsstripping the thread 011 the package (not shown) through pigtail 2 andacross the face of the machine on thread line A.

When plunger 51 of sequence timer cylinder 38 opens poppet valve 43 onthe retraction stroke, it also deactivates the spool valve 40 forstripping timer cylinder 36. The plunger 54 retracts at a controlledrate until it opens poppet valve 49. The interval of time the strippingtimer assembly 36 allows the thread to be stripped off the package canbe adjusted so a preset length of thread is stripped between tests.Since valve 23 is open, the opening of poppet valve 49 by return ofplunger 54 reverses spool valve 42 and starts another cycle. In thismode of operation, the apparatus therefore functions automatically toperform a series of tests at preset time intervals.

Similarly, to obtain single tests, the thread is strung up and allowedto strip off the package. The push button valve 22 is then depressed,permitting air to flow from source 35 through check valve 39, and theapparatus runs through one activation-deactivation cycle. The threadwill then recommence stripping off the package until the push buttonvalve 22 is again depressed, the toggle valve 23 opened or the strippingstopped manually.

Although pneumatic elements have been described and illustrated, it isapparent that electronic, hydraulic and other systems of control wouldfunction equally as well and could be used without departing from thespirit of our invention which accordingly is intended to be limited onlyby the scope of the appended claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. An apparatus for imparting tension to a thread for testpurposes, saidapparatus comprising: an aspirator to which the thread normally advancesunder low tension; a first clamp adapted to sequentially decelerate,stop and clamp the thread; a second clamp spaced from the first clampand adapted to grip the stopped thread; a constant tension devicelocated between the clamps, said device including a pair of axiallyfixed pulleys adapted for engagement by the clamped length of thread anda shaft carrying a third pulley and a counterweight, said shaft beingpivotally mounted for swinging movement to and from a position where thethird pulley rests on said clamped length between said pair of pulleys;instrumentation located adjacent the thread for testing a physicalproperty of said clamped length; and means for activating anddeactivating the clamps and said tension device in timed sequence, saidactivating-deactivating means including an extensible mechanism coupledto said shaft for its swinging movement from said position, said clampsand said tension device being located adjacent the normal path ofadvance to the aspirator.

2. The apparatus of claim 1 wherein the second clamp is located betweenthe first clamp and said aspirator.

3. The apparatus of claim 2 wherein said second clamp comprises anaxially fixed roll on one side of the thread and a reciprocably mountedroll on the opposite side of the thread, said activating-deactivatingmeans including an extensible mechanism coupled to the latter roll forreciprocating it to and from a position of clamping engagement with theaxially fixed roll.

4. The apparatus of claim 3 wherein is provided a drive mechanismcoupled to said axially fixed roll for metering a short length of threadback toward said pulleys, thereby permitting the weighted pulley toswing beyond the axially fixed pulleys.

5. The apparatus of claim 1 wherein said activating-deactivating meansincludes a sequence control timer coupled to said clamps and thetensioning device for their activation and deactivation in timedsequence and a measurement timer also coupled to the sequence controltimer for allowing a predetermined time interval for physical testingbetween activation and deactivation.

6. The apparatus of claim 5 wherein said activating-deactivating meansincludes a stripping timer coupled to the sequence control timer for itsautomatic reactivation after a predetermined length of thread hasadvanced away from the source.

References Cited UNITED STATES PATENTS 2,744,408 5/ 1956 Seney.2,875,609 3/1959 Seney. 3,273,380 9/1966 Seney. 1,913,120 6/1933 Kenyon73160 XR 1,941,917 1/1934 Schultz 7395.5 2,068,036 1/1937 Orling 73-460X FOREIGN PATENTS 754,919 8/1956 Great Britain.

RICHARD C. QUEISSER, Primary Examiner I. W. MYRACLE, Assistant ExaminerUS. Cl. X.R. 73-160

